Method for deep treatment of tail water of sewage treatment plant by using constructed wetlands

Abstract

The invention discloses a method for deep treatment of tail water of a sewage treatment plant by using constructed wetlands. The method comprises the following steps: S1, lifting sewage to be treatedinto a sedimentation tank by means of a lift pump room for pretreating the sewage, wherein particulate matters are precipitated in this step; S2, enabling the sewage to enter the surface flow constructed wetland from the sedimentation tank, wherein the pollutants in the sewage are further degraded; S3, enabling the sewage to enter the composite constructed wetland from the surface flow constructedwetland, wherein the pollutants are further degraded and denitrified to remove nitrogen; S4, enabling the sewage to enter ecological marsh wetland from the composite constructed wetland to further remove the pollutants in the water; S5, enabling the sewage to enter a natural ecological wetland with more ecological landscape characteristics from the ecological marsh wetland for carrying out the final treatment on the residual pollutants so as to obtain the up-to-standard tail water. The method provided by the invention is high in water purification efficiency, rapid in water through speed, andlow in construction cost at the early stage.

Description

technical field [0001] The invention relates to the field of water treatment, in particular to a method for advanced treatment of tail water of a sewage treatment plant by using artificial wetlands. Background technique [0002] At present, the effluent of most domestic sewage treatment plants basically meets the national "Comprehensive Wastewater Discharge Standard (GB8978-1996)" Grade A (the highest standard) or Grade B standard before it can be discharged into the water body. Compared with the minimum standard of "Surface Water Environmental Quality Standard (GB 3838-2002)", the effluent of sewage treatment plant still contains a large amount of COD Cr , NH 3 -N and TP. Therefore, the tail water discharge of sewage treatment plants is still an important source of pollution for some surface water bodies with low environmental capacity. In order to effectively protect the surface water environment, it is necessary to further treat the tail water of the sewage treatment p...

AI Technical Summary

Problems solved by technology

[0003] Although the tertiary treatment of the traditional sewage treatment plant can make the COD in the tail water Cr , NH 3 -N and TP meet the relevant standards in the "Environmental Quality Standards for Surface Water (GB 3838-2002)", but it is difficult to promote them on a large scale due to their high investment and operating costs

At the same time, a large number of facts also show that relying solely on the traditional tertiary treatment method of sewage treatment plants will lead to a large amount of use of chemicals and may cause secondary pollution of chemicals. It is difficult to fundamentally solve the problem of water pollution and can only delay its development trend.

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